Healthcare is rapidly transitioning from a core structure of individual practitioners (cowboys) to team-based care (pit crews). One such team-based model is the Accountable Care Unit (ACU), a care delivery system for inpatient units that combines: 1) unit-based teams, 2) nurse-physician partnered management, 3) unit-level performance data, and 4) structured interdisciplinary bedside rounds. At a demonstration unit at Emory University, data suggest that the ACU intervention significantly decreases mortality, length of stay, and central-line blood stream infections. However, our knowledge of how to implement such interventions is extremely limited, and the process of culture change in hospital units is poorly understood. While many healthcare interventions are commonly assumed to be technical and easily exported, the reality is that the implementation of simple interventions, like checklists, are dynamic social processes and their success is heavily dependent on both cultural and social context. This research will uncover this dynamic process of implementation by utilizing a natural experiment, as there are immediate plans to implement the ACU onto two additional hospital units. This marks an unusual opportunity to longitudinally study how the same intervention alters culture on three separate hospital units. This study will 1) describe these units at baseline and inform the implementation of the ACU, 2) characterize the transformation of units over the course of implementation, and 3) identify the activities, contextual factors, or other factors that accelerated or hindered the implementation process. Combining methods from quality improvement and ethnography, data collection includes semi- structured interviews, participant observation research, and commonly used surveys of teamwork and safety culture-incorporating perspectives from both caregivers and the implementation leaders. Data will be coded and analyzed using a combination of grounded theory, iterative constant comparison, and cross-case analysis. This research is particularly relevant for the AHRQ strategic goals of enhancing safety/quality, efficiency, and effectiveness of healthcare delivery-as this research directly supports the evaluation and study of an intervention that improves care, enhances outcomes, and lowers costs. In addition, the long-term aim is to generate both pragmatic recommendations and theoretical frameworks to further translational research and the implementation sciences.